<template>
  <div>
    <div
      class="mask"
      v-show="isShowSelect"
      @click="isShowSelect = !isShowSelect"
    ></div>
    <el-popover
      placement="bottom-start"
      :width="width"
      trigger="manual"
      v-model="isShowSelect"
      @hide="popoverHide"
    >
      <el-tree
        class="common-tree"
        :style="style"
        ref="tree"
        :data="TreeData"
        :props="defaultProps"
        :show-checkbox="multiple"
        :node-key="idKey"
        :check-strictly="checkStrictly"
        default-expand-all
        :expand-on-click-node="false"
        :check-on-click-node="multiple"
        :highlight-current="true"
        @node-click="handleNodeClick"
        @check-change="handleCheckChange"
      >
      </el-tree>
      <el-select
        :style="selectStyle"
        slot="reference"
        ref="select"
        :size="size"
        :value="selectedData"
        :multiple="multiple"
        :clearable="clearable"
        :collapse-tags="collapseTags"
        @click.native="isShowSelect = !isShowSelect"
        @remove-tag="removeSelectedNodes"
        @clear="removeSelectedNode"
        @change="changeSelectedNodes"
        class="tree-select"
        v-bind="$attrs"
      >
        <el-option
          v-for="item in options"
          :key="item.value"
          :label="item.label"
          :value="item.value"
        >
        </el-option>
      </el-select>
    </el-popover>
  </div>
</template>
<script>
import { isArray, isArrayEmpty } from "@/utils/validate";
export default {
  name: "select-tree",
  props: {
    // 树结构数据
    data: {
      type: Array,
      default() {
        return [];
      }
    },
    defaultProps: {
      type: Object,
      default() {
        return { children: "children", label: "text" };
      }
    },
    // 配置是否可多选
    multiple: {
      type: Boolean,
      default() {
        return false;
      }
    },
    // 配置是否可清空选择
    clearable: {
      type: Boolean,
      default() {
        return false;
      }
    },
    // 配置多选时是否将选中值按文字的形式展示
    collapseTags: {
      type: Boolean,
      default() {
        return false;
      }
    },
    idKey: {
      type: String,
      default() {
        return "id";
      }
    },
    nameKey: String,
    pIdKey: String,
    disabledKey: {
      type: String,
      default: ""
    },
    // 显示复选框情况下，是否严格遵循父子不互相关联
    checkStrictly: {
      type: Boolean,
      default() {
        return false;
      }
    },
    size: {
      type: String,
      default() {
        return "small";
      }
    },
    width: {
      type: String,
      default() {
        return "250px";
      }
    },
    height: {
      type: Number,
      default() {
        return 300;
      }
    },
    selectedVal: {
      type: [String, Number, Array],
      default() {
        return "";
      }
    }
  },
  data() {
    return {
      isShowSelect: false, // 是否显示树状选择器
      options: [],
      selectedData: "", // 选中的节点
      style: "height:" + this.height + "px;",
      selectStyle: `width:calc(${this.width});`,
      checkedIds: [],
      checkedData: []
    };
  },
  mounted() {
    this.initCheckedData();
  },
  methods: {
    // 单选时点击tree节点，设置select选项
    setSelectOption(node) {
      let tmpMap = {};
      tmpMap.value = node.key;
      tmpMap.label = node.label;
      this.options = [];
      this.options.push(tmpMap);
      this.$nextTick(() => {
        this.selectedData = node.key;
      });
    },
    // 单选，选中传进来的节点
    checkSelectedNode(checkedKeys) {
      var item = checkedKeys[0];
      this.$refs.tree.setCurrentKey(item);
      var node = this.$refs.tree.getNode(item.toString());
      if (node) {
        this.setSelectOption(node);
      }
    },
    // 多选，勾选上传进来的节点
    checkSelectedNodes(checkedKeys) {
      this.$refs.tree.setCheckedKeys(checkedKeys);
    },
    // 单选，清空选中
    clearSelectedNode() {
      this.selectedData = "";
      this.$refs.tree.setCurrentKey(null);
    },
    // 多选，清空所有勾选
    clearSelectedNodes() {
      var checkedKeys = this.$refs.tree.getCheckedKeys(); // 所有被选中的节点的 key 所组成的数组数据
      for (let i = 0; i < checkedKeys.length; i++) {
        this.$refs.tree.setChecked(checkedKeys[i], false);
      }
    },
    initCheckedData() {
      if (this.multiple) {
        // 多选
        if (!isArrayEmpty(this.checkedKeys)) {
          this.checkSelectedNodes(this.checkedKeys);
        } else {
          this.clearSelectedNodes();
        }
      } else {
        // 单选
        if (!isArrayEmpty(this.checkedKeys)) {
          this.checkSelectedNode(this.checkedKeys);
        } else {
          this.clearSelectedNode();
        }
      }
    },
    popoverHide() {
      if (this.multiple) {
        this.checkedIds = this.$refs.tree.getCheckedKeys(); // 所有被选中的节点的 key 所组成的数组数据
        this.checkedData = this.$refs.tree.getCheckedNodes(); // 所有被选中的节点所组成的数组数据
      } else {
        this.checkedIds = this.$refs.tree.getCurrentKey();
        this.checkedData = this.$refs.tree.getCurrentNode();
      }
      this.$emit("popoverHide", this.checkedIds, this.checkedData);
    },
    // 单选，节点被点击时的回调,返回被点击的节点数据
    handleNodeClick(data, node) {
      if (!this.multiple) {
        this.setSelectOption(node);
        this.isShowSelect = !this.isShowSelect;
        // this.$nextTick(()=>{})
        this.$emit("change", node.key);
      }
    },
    // 多选，节点勾选状态发生变化时的回调
    handleCheckChange() {
      var checkedKeys = this.$refs.tree.getCheckedKeys(); // 所有被选中的节点的 key 所组成的数组数据
      this.options = checkedKeys.map(item => {
        var node = this.$refs.tree.getNode(item); // 所有被选中的节点对应的node
        let tmpMap = {};
        tmpMap.value = node.key;
        tmpMap.label = node.label;
        tmpMap.disabled = node.disabled;
        return tmpMap;
      });
      this.selectedData = this.options.map(item => {
        return item.value;
      });
      this.$emit("change", this.selectedData);
    },
    // 多选,删除任一select选项的回调
    removeSelectedNodes(val) {
      this.$refs.tree.setChecked(val, false);
      var node = this.$refs.tree.getNode(val);
      if (!this.checkStrictly && node.childNodes.length > 0) {
        this.treeToList(node).map(item => {
          if (item.childNodes.length <= 0) {
            this.$refs.tree.setChecked(item, false);
          }
        });
        this.handleCheckChange();
      }
      this.$emit("change", this.selectedData);
    },
    treeToList(tree) {
      var queen = [];
      var out = [];
      queen = queen.concat(tree);
      while (queen.length) {
        var first = queen.shift();
        if (first.childNodes) {
          queen = queen.concat(first.childNodes);
        }
        out.push(first);
      }
      return out;
    },
    // 单选,清空select输入框的回调
    removeSelectedNode() {
      this.clearSelectedNode();
      this.$emit("change", this.selectedData);
    },
    // 选中的select选项改变的回调
    changeSelectedNodes(selectedData) {
      // 多选,清空select输入框时，清除树勾选
      if (this.multiple && selectedData.length <= 0) {
        this.clearSelectedNodes();
      }
      this.$emit("change", this.selectedData);
    }
  },
  model: {
    prop: "selectedVal",
    event: "change"
  },
  computed: {
    //组装Treedata
    TreeData() {
      if (this.data.length == 0) {
        return [];
      }
      let { data, idKey, pIdKey, nameKey, disabledKey } = this;
      if (!pIdKey) {
        return this.data;
      }
      let _treedata = [];
      // id: 1,label: '一级 1', children: [{
      let getChildren = item => {
        let thisc = data.search({ [pIdKey]: item[idKey] });
        thisc.forEach(thisc_item => {
          thisc_item.children = getChildren(thisc_item);
        });
        thisc.disabled = item[disabledKey];
        return thisc;
      };
      //得到子菜单
      data.forEach(item => {
        //是否有子
        let c = data.search({ [pIdKey]: item[idKey] });
        item.disabled = item[disabledKey];
        if (c.length != 0) {
          item.children = getChildren(item);
          _treedata.push(item);
        }
      });
      this.$nextTick(() => {
        this.initCheckedData();
      });
      return _treedata;
    },
    checkedKeys() {
      let val = this.selectedVal;
      if (!val) {
        return [];
      }
      if (!isArray(val)) {
        val = [val];
      }
      return val;
    }
  },
  watch: {
    isShowSelect(val) {
      //如果是显示 先判断禁用状态
      if (val && this.$refs.select.$children[0].disabled) {
        this.isShowSelect = false;
      }
      // 隐藏select自带的下拉框
      this.$refs.select.blur();
    },
    checkedKeys(val) {
      if (!val) {
        return;
      }
      if (!isArray(val)) {
        val = [val];
      }
      // this.checkedKeys = val;
      this.initCheckedData();
    },
    nameKey: {
      handler(newName, oldName) {
        this.defaultProps.label = newName;
      },
      immediate: true
    },
    width: {
      handler(newName, oldName) {
        this.$nextTick(() => {
          this.$refs.tree.$el.style.width =
            this.$refs.select.$el.offsetWidth - 24 + "px";
        });
      },
      immediate: true
    }
  }
};
</script>

<style scoped>
.mask {
  width: 100%;
  height: 100%;
  position: fixed;
  top: 0;
  left: 0;
  opacity: 0;
  z-index: 11;
}
.common-tree {
  overflow: auto;
}
.tree-select {
  z-index: 111;
}
</style>
